Like others have said, Alex Shelley suffered a broken collarbone several months back. As a result, Chris Sabin, for the most part, has been MIA during this time but the word on the internet is that TNA is going to focus them primarily as singles competitors for now.
On one hand, it's natural to want The Guns as a tag team. They're a great team and the tag team scene in TNA right now needs great teams as it's weaker now than it's been in a very long time. At the same time, The Guns have been together for a long time. Aside from Beer Money, there isn't another team in TNA that's even remotely on their level and TNA just can't keep them feuding with Beer Money.